Apparatus for removing gases from liquids



June 24, 1930. l.. D. MxLLs 1,757,006

APPARATUS FOR REMOVING' GASES FROM LIQUIDS Filed June 15, 1928 ATTORNEY 4Patented June 24, v193i.)

UNITED STATES PATENT OFFICE LOUIS D. `MILLS', 0F PALO ALTO, CALIFORNIA, ASSIGNOR TO THE vMERRILL COMPANY,

OF SAN FRANCISCO, CALIFORNIA,

A CORPORATION OF CALIFORNIA APPARATUS Fon RMVING GASES FROM LIQUIDS Application led .Tune 13,

' The invention relates to an improvement in apparatus for removing dissolved gases from liquids and more Aespecially from cyanide Athe solution from mixing with the solution solutions prior to precipitating the dissolved metals, such as gold and silver, from such solutions.

It is' common practice to remove dissolved gases from cyanide solutionsby passing the solution through a closed vessel, technically called the receiver, within which a high vacuum is maintained. The receiver usually contains grids or checker workover which the solution is fiowed and by means of which it is broken up into thin films and finely divided streams, thus exposing a maximum of surface of the solution to the relatively loW absolute pressure within the receiver, with the result that t-he dissolved gases are evaporated or removed from the solution and are withdrawn from the receiver by the vacuumizing means. The solution from which the dissolved gases have been removed accumulates in the bottom of the receiver and is withdrawn therefrom by any suitable means, as by'elevating the receiver to a suiicient height to permit free discharge of the solution from the receiver through al submerged outlet. Or the solution may be withdrawn by means of a pump suitably sealed to preventA ingress of air.v The amount of solution introduced solution gathering in the bottom of the receiver is maintained 'at al suticient depth to prevent gases which have been removed from being discharged through the outlet orifice. It has been found in the actual operation off x apparatus of this character that where relatively large volumes of solution are passed through the receiver, and conseqluentlythere is a rapid flow through the out et, a vortex or swirl is thereby created in the solution in the bottom of the receiver, even though the solution is maintained at a considerable depth. This vortex or swirl of the solution being` discharged through the `outlet in the bottom of the receiver frequently causes substantial amounts of the gases which have been removed from the solution to. mingle with -pipe 6 into the receiver 1 is controlled by a solution therein.

1928. Serial No. 284,924.

p tion.

One object of the invention is to prevent the gases which have been removed from the solution in the receiver from mingling with or being entrained in the solution discharging'from the receiver. Another object of the invention is to(prevent the entraining of the removed gases'in the discharging solution by preventing the formation of a vortex or swirl in the solution at the outlet of the receiver. A'further object of the invention is to accomplish this purpose without increasing the depth of the solution maintained in the bottom of the receiver.

' In the-\ accompanying dra-wings Fig. 1

isl

a diagrammatic representation of a deaeratand to which the vortex preventing device of the invention is applied, comprises areceiver 1 in the form of an upright tank, connected by the pipe 2 with a vacuum pump 3. An enlargement 4 in the pipe 2 provided with baies prevents moisture from being drawn lfrom the receiver 1 into the pump 3. The receiver 1 receives its supply of solution to` be ldeaerated from -astorage tank 5 through the pipe 6, the lower endv of which is located in v the lower part of the tank 5, and the u per end of which discharges into the top o the receiver 1. The flow of solution through the butteriiy valve 7 provided with an arm 8 pivotally connected by a link 9 with the arm 10 of lthe lusual float (not shown) within the receiver 1 for controlling the level of the The tank 5 is supplied with solution to be deaerated through the pipe 11 provided with the hand operated valve 12. The level I13 of the solution 14 in the tank is controlled by a float 15 mounted on the outer endof an arm 100 la a 16 connected with a valve 17 in the pipe 11. The vacuum pump 3 causes the pressure in the receiver 1 to be reduced and the solution to flow from the tank 5 up through the pipe 6 and into the top of the receiver 1, whence it passes down through the usual means for dividing it into small particles so that the vacuum may be effective in withdrawing the d'issolvdor entrained air therefrom. Zhen the valve 7 in the lpipe 6 is closed by the rising of the float in the receiver l, thereby perl mitting the level of the solution in the tank 5 to rise. the supply of solution to the tank 5 is shut off by the risinglr of the float 15 and the closing of the valve 17 in the pipe 11,.

The deaerated liquid is drawn from the bottom of the receiver l through the pipes 1S and 1S` by means of a centrifugal pump 19 which i`s located in the tank 5 and submerged under the solution 14 therein. Connected with the discharge end. of theA pump 19 is an upright pipe 20. The pump 19 is driven by the motor 2l through the shaft the -outer ends of the shaft '22 and the shaft`23 where the. shaft 22 enters the side of the pump 19 is sealed by the gland 30. The gland 30 prevents any of the untreated solution 1% in the tank 5 from enteringthe pump 19 and mixing with the deaeratedsolution withdrawn from the receiver 1 and discharged from the pipe 20. Thus air in any form is effectuallyprevented from entering the de-` aerated solution discharged from` the receiver.

` The means of the present invention for preventing-the formation of a vortex-in the -solution discharging from the bottom of the receiver comprises a series of thin, radial walls or baffle plates, four in the present instance, mounted in the bottom 31 of the receiver 1, The baflie plates, indicated generally at 32, are vertically arranged and comprise a laterally extending part 33 supported on the bottom surface 3l of the receiver 1 andan inner downwardly extending part 34 received wit-hin the upper part of the discharge ori' fice or outlet 35 of the receiverV and with which the pipe 18 is connected. The baiiie Y l plates 32 are arranged in the form of a Cross and are spaced substantially equi-distant apart. The bottom surfaces of the laterally v extendingparts 33 of thebaftie plates curve in conformity with the curved bottom 31 of the receiver 1, and the top edges of the battle plates are straight and all arranged on y substantiallj' the same plane. A cover part 36 preferably in the form of a circular disk,

is mounted upon the baie plates 32 centrally of the discharge outlet.

Then the receiver l has been provided with the vortex preventing device of the present invention, as described above, the solution may 'be dischargedthrough t-he outlet 19 at high velocity without liability of creating a vortex or swirl in the solution in the bottom of thereceiver although the solution be maintained ata relatively shallow depth. To form a vortex or swirl it is necessary for the solution to rotate and this the radially extending baiile )lates 32 etfectually prevent. F ormation of the vortex is further prevented by the plate 36 secured to t-he upper edges of the central portions of the baiiie'plates. 'The batlie plates. are of such height and the plate 36 Vof such diameter as-t'o provide sufficient space for the solution to pass freely` through the discharge orifice 35 and into the pipe 18.

Having thus described the invention what scribed including a tank having an outlet inv the bottomthereof for the dischargek of liq uid therethrough, means located in the bottom of the tank for preventing the discharging liquid from swirling and forming a v,or-

tex in the liquid in the tank comprising a series of vertical, radially extending baffle plates, the inner parts of said baffle plates being located over the outlet and the outer parts of said bailie plates being supported by` their lower edges on the bottom of the tank, and a flat, horizontally arranged plate supported on the upper edges of the baffle plates and arranged substantially co-axially with the outlet. Y

" 2. In an apparatus of the character described including the tank having a curved bottom with'an outlet therein for the discharge of liquid therethrough, means for preventing the Jliquid discharging -through I the outlet from swirlingand forming a vor- ,i

tex in theliquid in the` tank comprising a series of vertically arranged baiie plates, the lower edges of the baille plates .being curved in conformity with the curve of the bottom of the tank and rest-ing ,thereonand t-he upper edges of the baffle plates being straight and all lying in substantially the same plane. and

ay disk resting on theupper edges of the baffle plates and located substantially co-a-xially with the outlet.

' LOUIS D. MILLS` lno 

